I'm somewhat new to photography...scratch that...I am new to this part of photography...I do not fully understand the lens situations, but I am hearing that wide angle lenses on one camera, might not be wide angle on another....

I have a Canon Rebel XTi....I just purchased the 28-135mm wide angle...(or is this not wide angle?)

But I am also purchasing the Canon 7D next week...I know my lenses need to stay in the EF family, but I really need a wide angle...can someone help me out in this dept and help me understand what I am clearly missing?

I'm not sure about the 7D, but I think the XTi has a crop factor of 1.6. That means that while the lens is 28-135, your photos will appear to be shot with a 45-218. If you don't want this then you need a full frame camera, which has a 1:1 crop factor.

I don't know if the 7D is a full frame, some one who shoots with Canon can give you a better response.

28mm x 1.6 = 44.8 35mm equivalent angle of view, so 28mm is not really "wide-angle" on your Rebel XTi. TO get into wide-angle, one needs a 35mm equivalent of at least 28mm, so that means on a crop-body d-slr like your Rebel, one needs an 18 or 17mm "bottom end", as on say an 18-55mm kit zoom lens, in order to get wide-angle views.

Terms like 'wide angle' get tossed around. That was used on that lens, back when it was designed for 35mm film cameras....and even then, I wouldn't consider it all that wide.

You need to go by the numbers, as Derrel has kindly shown.

So for a 'typical wide angle view', on your camera, you'd want a lens that zooms down to 17mm or 18mm.

This is true of all cameras that have a similar sized sensor to what you have. That includes all the Digital Canon Rebels models, the two digit models (40D, 50D etc.) and the 7D. The 5D has a larger sensor (same size as 35mm film) so it gives you a wider view. The Canon 1Ds is also 'full frame' and the 1D is in between.

A lens said to be wide angle is not always wide angle. Just as a lens said to be macro is not always true macro.

Anything under 50mm is wide and anything over 50mm is telephoto. So that would technically make the 28-135 somewhat wide and somewhat telephoto.

Look for what some refer to as the ultra wide.
I have a Canon 10-22 which I love. Works great on my XSI and on my 7D. With the x1.6 crop factor, it makes the lens an effective 16-35, which is wide.
You have other options such as a Sigma 10-20
Or go a little less wide with a Canon 17-55mm, 16-35mm..